Methods of forming V0 structures for semiconductor devices that includes recessing a contact structure

ABSTRACT

One illustrative method disclosed herein includes, among other things, forming a source/drain contact structure between two spaced-apart transistor gate structures, recessing the source/drain contact structure to define a source/drain contact etch cavity and depositing a conformal second layer of insulating material above a first layer of insulating material and in the source/drain contact etch cavity. The method also includes forming a third layer of insulating material above the conformal second layer of insulating material, forming an opening in the conformal second layer of insulating material and forming a V0 via that is conductively coupled to the exposed portion of the recessed source/drain contact structure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Generally, the present disclosure relates to the manufacture ofsophisticated semiconductor devices, and, more specifically, to variousmethods of forming V0 structures for semiconductor devices that includesrecessing a contact structure and various semiconductor devices havingthe resulting V0 structural configurations.

2. Description of the Related Art

In modern integrated circuits, such as microprocessors, storage devicesand the like, a very large number of circuit elements, especiallytransistors, are provided and operated on a restricted chip area.Generally, in complex circuitry including complex logic portions, MOStechnology is presently a preferred manufacturing technique in view ofdevice performance and/or power consumption and/or cost efficiency. Inintegrated circuits fabricated using MOS technology, field effecttransistors (FETs), such as planar field effect transistors and/orFinFET transistors, are provided that are typically operated in aswitched mode, i.e., these transistor devices exhibit a highlyconductive state (on-state) and a high impedance state (off-state). Thestate of the field effect transistor is controlled by a gate electrode,which controls, upon application of an appropriate control voltage, theconductivity of a channel region formed between a drain region and asource region.

To improve the operating speed of FETs, and to increase the density ofFETs on an integrated circuit device, device designers have greatlyreduced the physical size of FETs over the years, particularly thechannel length of transistor devices. As a result of the reduceddimensions of the transistor devices, the operating speed of the circuitcomponents has been increased with every new device generation, and the“packing density,” i.e., the number of transistor devices per unit area,in such products has also increased during that time. Such improvementsin the performance of transistor devices has reached the point where onelimiting factor relating to the operating speed of the final integratedcircuit product is no longer the individual transistor element but theelectrical performance of the complex wiring system that is formed abovethe device level where the actual semiconductor-based circuit elements,such as transistors, are formed in and above the semiconductorsubstrate.

Typically, due to the large number of circuit elements and the requiredcomplex layout of modern integrated circuits, the electrical connectionsor “wiring arrangement” for the individual circuit elements cannot beestablished within the same device level on which the circuit elementsare manufactured. Accordingly, the various electrical connections thatconstitute the overall wiring pattern for the integrated circuit productare formed in one or more additional stacked so-called “metallizationlayers” that are formed above the device level of the product. Thesemetallization layers are typically comprised of layers of insulatingmaterial with conductive metal lines or conductive vias formed in thelayers of material. Generally, the conductive lines provide theintra-level electrical connections, while the conductive vias providethe inter-level connections or vertical connections between differentlevels. These conductive lines and conductive vias may be comprised of avariety of different materials, e.g., copper, with appropriate barrierlayers, etc. The first metallization layer in an integrated circuitproduct is typically referred to as the “M1” layer, while the conductivevias that are used to establish electrical connection between the M1layer and lower level conductive structures (explained more fully below)are typically referred to as “V0” vias. The conductive lines andconductive vias in these metallization layers are typically comprised ofcopper, and they are formed in layers of insulating material using knowndamascene or dual-damascene techniques. Additional metallization layersare formed above the M1 layer, e.g., M2/V1, M3/V2, etc. Within theindustry, conductive structures below the V0 level are generallyconsidered to be “device-level” contacts or simply “contacts,” as theycontact the “device” (e.g., a transistor) that is formed in the siliconsubstrate.

FIG. 1A is a cross-sectional view of an illustrative integrated circuitproduct 10 comprised of a plurality of transistor devices 15 formed inand above a semiconductor substrate 12. A schematically depictedisolation region 13 has also been formed in the substrate 12. In thedepicted example, the transistor devices 15 are comprised of anillustrative gate structure, i.e., a gate insulation layer 16 and a gateelectrode 18, a gate cap layer 20, a sidewall spacer 22 andsimplistically depicted source/drain regions 24. At the point offabrication depicted in FIG. 1A, layers of insulating material 17A, 17B,i.e., interlayer dielectric materials, have been formed above theproduct 10. Other layers of material, such as contact etch stop layersand the like, are not depicted in the attached drawings. Also depictedare illustrative source/drain contact structures 28 which include acombination of a so-called “trench silicide” (TS) region 28A and a metalregion 28B (such as tungsten). In the depicted process flow, the uppersurface of the source/drain contact structures 28 is approximatelyplanar with the upper surface of the gate cap layers 20. Also depictedin FIG. 1A are a plurality of so-called “CA contact” structures 32 andan illustrative gate contact structure 31 which is sometimes referred toas a “CB contact” structure. The CA contact structures 32 and the CBcontact structure 31 are formed to provide electrical connection betweenthe underlying devices and the V0 via level. The CA contact structures31 are formed to provide electrical contact to the source/drain contactstructures 28, while the CB contact 31 is formed so as to contact aportion of the gate electrode 18 of one of the transistors 15. In a planview (not shown), the CB contact 31 is positioned vertically above theisolation region 13, i.e., the CB contact 31 is not positioned above theactive region defined in the substrate 12. The CA contact structures 32may be in the form of discrete contact elements, i.e., one or moreindividual contact plugs having a generally square-like or cylindricalshape, that are formed in an interlayer dielectric material, as shown inFIG. 1A. In other applications (not shown in FIG. 1A), the CA contactstructures 32 may also be a line-type feature that contacts underlyingline-type features, e.g., the source/drain contact structures 28 thatcontact the source/drain region 24 and typically extend across theentire active region on the source/drain region 24. Typically, the CBcontact 31 is in the form of a round or square plug.

In one embodiment, the process flow of forming the source/drain contactstructures 28, CA contacts 32 and CB contact 31 may be as follows. Aftera first layer of insulating material 17A is deposited, source/draincontact openings are formed in the first layer of insulating material17A that expose portions of underlying source/drain regions 24.Thereafter, traditional silicide 28A is formed through the source/draincontact openings, followed by forming a metal 28B (such as tungsten) onthe metal silicide regions 28A, and performing a chemical mechanicalpolishing (CMP) process down to the top of the gate cap layer 20. Then,a second layer of insulating material 17B is deposited. In olderdevices, the packing density was such that the openings in the layer ofinsulating material 17B for both the CA contact structures 32 and the CBcontact structure 31 could be formed using a single patterned etch mask.However, as packing densities have increased with newer devicegenerations, the openings in the layer of insulating material 17B forthe CA contact structures 32 and the CB contact structure 31 are formedseparately using two different masking layers—a CA masking layer and aCB masking layer. Thus, in one illustrative process flow, using the CAmasking layer, the contact openings for the CA contacts 32 are formedfirst in the second layer of insulating material 17B so as to exposeportions of the tungsten metallization 28B of the underlyingsource/drain contact structure 28. Then the CA masking layer is removedand the CB masking layer is formed over the second layer of insulatingmaterial 17B and in the previously formed CA contact openings formedtherein. Next, using the CB masking layer, the opening for the CBcontact 31 is formed in the second layer of insulating material 17B andthrough the gate cap layer 20 so as to expose a portion of the gateelectrode 18. Thereafter, the CB masking layer is removed and the CAcontacts 32 and the CB contact 31 are formed in their correspondingopenings in the second layer of insulating material 17B by performingone or more common metal deposition and CMP process operations, usingthe second layer of insulating material 17B as a polish-stop layer toremove excess material positioned outside of the contact openings. TheCA contacts 32 and CB contact 31 typically contain a uniform body ofmetal, e.g., tungsten, and may also include one or more metallic barrierlayers (not shown) positioned between the uniform body of metal and thelayer of insulating material 17B. The source/drain contact structures28, the CA contacts 32 and the CB contact 31 are all considered to bedevice-level contacts within the industry.

Also depicted in FIG. 1A is the first metallization layer—the so-calledM1 layer—of the multi-level metallization system for the product 10formed in a layer of insulating material 34, e.g., a low-k insulatingmaterial. A plurality of conductive vias—so-called V0 vias 40—areprovided to establish electrical connection between the device-levelcontacts—CA contacts 32 and the CB contact 31—and the M1 layer. The M1layer typically includes a plurality of metal lines 38 that are routedas needed across the product 10.

FIGS. 1B-1F depict a semiconductor device with self-aligned contactswhere a line-type CA structure 30 (FIG. 1C) was formed using oneillustrative prior art technique. In this illustrative example, the CAcontact structure 30 is not formed in a separate layer of insulatingmaterial, as was the CA contact structures 32 (in the layer 17B)described above. Rather, in this process flow, the upper metal portionof the source/drain contact structure (positioned below the level of thegate cap layers 20) serves as the “CA contact structure.” In thisprocess flow, only the CB contact is formed above the gate cap layers 20in a separate layer of insulating material. That is, using this processflow, the formation of a separate CA contact in a layer of insulatingmaterial positioned above the level of the gate cap layers 20 isomitted, and only a single masking layer—the CB masking layer—is used toform the equivalent of the CA contacts 32 and the gate contact 31described above. However, relative to the process flow described inconnection with FIG. 1A above, this process flow does require theformation of an extended-length V0 via to contact the CA contactstructure 30, as described more fully below.

FIG. 1B depicts an illustrative prior art integrated circuit product 10comprised of first and second transistors 15A, 15B formed in and above asemiconductor substrate 12. In the depicted example, each of thetransistors 15A, 15B is comprised of the gate insulation layer 16 andthe gate electrode 18, the gate cap layer 20 and a sidewall spacer 22.Typically, the gate cap layer 20 and the sidewall spacer 22 are made ofa material such as silicon nitride and their purpose is to effectivelyencapsulate and protect the gate structure. The gate structure may beformed using either gate first or replacement gate techniques. In thecase where the gate structure is formed using replacement gatetechniques, the cap layer 20 is formed after a sacrificial gatestructure (not shown) is removed and after a replacement gate structure(e.g., high-k insulation layer and one or more metal layers is formed inthe position previously occupied by the removed sacrificial gatestructure). With continuing reference to FIG. 1B, also depicted areillustrative raised source/drain regions 24 and a layer of insulatingmaterial 26 (e.g., silicon dioxide) that is formed above the product 10and planarized.

FIGS. 1B-1F will only depict the formation of a source/drain contactstructure between the gate structures 15A, 15B so as to facilitateexplanation. Those skilled in the art will appreciate that, in practice,a corresponding source/drain contact structure will be formed for all ofthe source/drain regions, i.e., on the source/drain region to the leftof the gate structure 15A and on the source/drain region to the right ofthe gate structure 15B.

Accordingly, FIG. 1C depicts the product 10 after several processoperations were performed to form a so-called self-aligned contact thatis conductively coupled to the raised source/drain region 24. First, apatterned etch mask (not shown) was formed above the product 10 so as toexpose the area between the gate structures 15A-15B. Thereafter, atleast the insulating material 26 was etched selectively relative to thesidewall spacers 22 and the gate cap layer 20 to thereby expose theraised source/drain region 24. Next, the patterned etch mask was removedand a trench silicide structure 28A was formed on the exposedsource/drain region 24 by performing traditional silicide processingoperations. Thereafter, a line-type CA contact structure 30 comprisedof, for example, tungsten, was formed so as to be conductively coupledto the trench silicide structure 28A. In one embodiment, the line-typeCA contact structure 30 may be formed of a material such as tungsten andit may extend across substantially the entire active region of thesubstrate 12, just like the trench silicide structure 28A. In oneparticular example, the line-type CA contact structure 30 may be formedby overfilling the area above the trench silicide structure 28A withtungsten and thereafter performing a CMP process.

FIG. 1D depicts the product 10 after several process operations wereperformed. First, a layer of material 32 having a substantially uniformthickness was formed above the product depicted in FIG. 1C. Thesubstantially uniform thickness of the layer of material 32 may varydepending upon the particular application. In one example, the layer ofmaterial 32 may be a material such as N-block (SiCNH). Thereafter, apatterned layer of insulating material 34, such as a low-k material (kvalue less than 3.3), having an opening 34A formed therein, was formedabove the layer of material 32. The product depicted in FIG. 1D is theresult of initially blanket depositing the layer of insulating material34 above the product 10, and thereafter patterning the layer of material34 through a patterned etch mask (not shown) so as to form the patternedlayer of insulating material 34, with the opening 34A, as depicted inFIG. 1D.

FIG. 1E depicts the product 10 after several process operations wereperformed. First, the layer of material 32 was patterned using apatterned etch mask (not shown) so as to define the opening 32A, asdepicted in FIG. 1E. The opening 32A is for the conductive V0 via 40that will be subsequently formed therein. Ideally, the opening 32A willbe relatively large in the lateral width direction so that the resultingV0 via 40 will also be relatively large—a “fat” V0. A relatively largerV0 is desirable in that it reduces the electrical resistance of the V0structure 40 and it makes it easier to actually contact the underlyingCA contact 30, i.e., the chances of missing the CA contact 30 decreaseif the V0 via is relatively wide. Then, the conductive lines 38 andconductive V0 vias 40 were formed in the openings 34A, 32A,respectively, by depositing one or more conductive materials, e.g.,barrier layers and copper, and performing a polarization process toremove excess conductive materials positioned outside of the opening34A. FIG. 1E depicts an idealized V0 structure 40 that results when theetch process that is performed to form the opening 32A in the materiallayer 32 is timed perfectly such that there is effectively noconsumption of the underlying gate cap layers 20 exposed by the opening32A. Note that, in this process flow, the V0 via must extend down to atleast the level of the upper surface of the gate cap layer 20 so thatelectrical contact may be made to the CA contact 30.

FIG. 1F depicts a situation wherein the idealized V0 structure 40depicted in FIG. 1D is not achieved. As noted above, the opening 32A inthe material layer 32 is formed such that it is relatively wide so thatthe ultimate V0 via will also be relatively wide or “fat.” As shown inFIG. 1F, the width of the opening 32A is such that it typically overlapsthe gate cap layer 20 of one or both of the transistors, as indicated bythe dimensioned arrows 35. Unfortunately, there is typically little etchselectivity between the material of the material layer 32, which isfrequently N-block, and the material of the gate cap layers 20, which istypically silicon nitride. As a result, if the etch process that isperformed to form the opening 32A in the material layer 32 is not timedperfectly, some or all of the underlying gate cap 20 may also beconsumed, thereby exposing a portion of the gate electrode 18. As aresult, when the V0 via 40 is formed, the V0 via 40 may actually contactthe exposed gate structures 18, as indicated in the dashed lines 37.Such a situation results in an electrical short between at least the V0structure 40 (and perhaps the CA contact 30) and the gate electrode 18.Such a situation can result in complete device failure.

The present disclosure is directed to various methods of forming V0structures for semiconductor devices, and various semiconductor deviceshaving the resulting V0 structural configurations, that may solve orreduce one or more of the problems identified above.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an exhaustive overview of the invention. It is notintended to identify key or critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts in a simplified form as a prelude to the more detaileddescription that is discussed later.

Generally, the present disclosure is directed to various methods offorming V0 structures for semiconductor devices that includes recessinga contact structure and various semiconductor devices having theresulting V0 structural configurations. One illustrative methoddisclosed herein includes, among other things, forming a source/draincontact structure between two spaced-apart transistor gate structures,recessing the source/drain contact structure to define a recessedsource/drain contact having a recessed upper surface, wherein therecessing of the source/drain contact structure defines a source/draincontact etch cavity, and performing a conformal deposition process todeposit a conformal second layer of insulating material above a firstlayer of insulating material, in the source/drain contact etch cavityand on the recessed upper surface of the recessed source/drain contact.In this example the method also includes forming a third layer ofinsulating material above the conformal second layer of insulatingmaterial, forming an opening in the conformal second layer of insulatingmaterial so as to expose at least a portion of the recessed uppersurface of the recessed source/drain contact, and forming a V0 via suchthat it is conductively coupled to the exposed portion of the recessedsource/drain contact structure, the V0 via being at least partiallypositioned in the opening in the conformal second layer of insulatingmaterial.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIGS. 1A-1F depict a semiconductor device with self-aligned contactswhere a line-type CA structure was formed using one illustrative priorart technique;

FIGS. 2A-2F depict various illustrative methods disclosed herein forforming V0 structures for semiconductor devices and devices that includethe resulting V0 structural configurations; and

FIGS. 3A-3J depict other illustrative methods disclosed herein forforming V0 structures for semiconductor devices that includes recessinga contact structure and devices that include the resulting V0 structuralconfigurations.

While the subject matter disclosed herein is susceptible to variousmodifications and alternative forms, specific embodiments thereof havebeen shown by way of example in the drawings and are herein described indetail. It should be understood, however, that the description herein ofspecific embodiments is not intended to limit the invention to theparticular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Various illustrative embodiments of the invention are described below.In the interest of clarity, not all features of an actual implementationare described in this specification. It will of course be appreciatedthat in the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present subject matter will now be described with reference to theattached figures. Various structures, systems and devices areschematically depicted in the drawings for purposes of explanation onlyand so as to not obscure the present disclosure with details that arewell known to those skilled in the art. Nevertheless, the attacheddrawings are included to describe and explain illustrative examples ofthe present disclosure. The words and phrases used herein should beunderstood and interpreted to have a meaning consistent with theunderstanding of those words and phrases by those skilled in therelevant art. No special definition of a term or phrase, i.e., adefinition that is different from the ordinary and customary meaning asunderstood by those skilled in the art, is intended to be implied byconsistent usage of the term or phrase herein. To the extent that a termor phrase is intended to have a special meaning, i.e., a meaning otherthan that understood by skilled artisans, such a special definition willbe expressly set forth in the specification in a definitional mannerthat directly and unequivocally provides the special definition for theterm or phrase.

The present disclosure is directed to various methods of forming V0structures for semiconductor devices that includes recessing a contactstructure, and various semiconductor devices having the resulting V0structural configurations. As will be readily apparent to those skilledin the art upon a complete reading of the present application, themethods disclosed herein may be employed with a variety of differenttechnologies, e.g., NMOS, PMOS, CMOS, etc., and in manufacturing avariety of different integrated circuit products, including, but notlimited to, logic products, memory products, etc. As will be appreciatedby those skilled in the art after a complete reading of the presentapplication, the methods disclosed herein may also be employed whenmanufacturing a variety of different type devices, e.g., planar devices,FinFET devices, nanowire devices, etc. Lastly, the gate structures forthe illustrative transistor devices depicted herein may be formed usingeither “gate-first” or “replacement gate” manufacturing techniques. Withreference to the attached figures, various illustrative embodiments ofthe methods and devices disclosed herein will now be described in moredetail.

FIGS. 2A-2F depict various illustrative methods disclosed herein forforming V0 structures. FIG. 2A is a simplified view of an illustrativesemiconductor product 100 at an early stage of manufacturing thatcorresponds to that depicted in FIG. 1C above, i.e., after a line-typeCA contact 30 was formed. That is, the CA contact 30 depicted in thesedrawings was formed without the use of a traditional CA masking layer.FIGS. 2A-2F will depict the formation of a source/drain contactstructure (i.e., the TS structure 28A and the CA contact 30) above eachof the source/drain regions 24. As depicted, the upper surfaces of theCA contact 30 are substantially planar with the upper surface of thegate cap layers 20.

FIG. 2B depicts the product 100 after a layer of material 102 having anon-uniform thickness was formed on the product. More specifically, thenon-uniform thickness layer of material 102 is formed such that itsthickness 102B above the silicon nitride gate cap layers 20 issubstantially thicker than its thickness 102A above the tungsten CAcontact structures 30. In one illustrative embodiment, the non-uniformthickness layer of material 102 may be formed such that the thickness102B is at least 10-30 nm greater than the thickness 102A. In absoluteterms, the thickness 102A may fall within the range of about 5-25 nm,while the thickness 102B may fall within the range of about 15-55 nm. Inone illustrative example, the non-uniform thickness layer of material102 may be a layer of silicon nitride that is formed by the TELOSprocess (by LAM Research™) wherein the silicon nitride materialselectively forms on the silicon nitride gate cap layer 20 at a muchfaster rate than it does on the tungsten CA contacts 30. In general,this process operation involves coating the upper metal surface of thetungsten CA contacts 30 with a self-assembled monolayer (SAM—not shown)so as to retard the growth of the layer of material 102 above the CAcontacts 30. Generally, this SAM makes the metal surface hydrophobic.Accordingly, the layer of material 102 will grow at a faster rate abovethe silicon nitride gate cap layers 20 than it does above the uppermetal surfaces of the metal CA contacts 30.

FIG. 2C depicts the product 100 a layer of insulating material 104, suchas a low-k material (k value less than 3.3), was blanket deposited abovethe product 100.

FIG. 2D depicts the product 100 after the layer of insulating material104 was patterned using a patterned etch mask (not shown) so as todefine an opening 104A in the layer of insulating material 104. Theopening 104A exposes a portion of the non-uniform thickness layer ofmaterial 102 for further processing.

FIG. 2E depicts the product 100 after several process operations wereperformed. First, a patterned etch mask 105 (such as a patterned layerof photoresist) having an opening 105A was formed above the product 100.The opening 105A corresponds to an opening for a V0 via that will beformed in the non-uniform thickness layer of material 102 to establishelectrical contact to the underlying CA contact 30. So as to facilitateexplanation, only the formation of a V0 via for the middle CA contact 30will be depicted in the following drawings. Of course, as will beappreciated by those skilled in the art, a similar V0 via will be formedfor each of the CA contacts 30. Thereafter, an etching process wasperformed through the patterned etch mask 105 so as to define an opening102X in the non-uniform thickness layer of material 102. The opening102X exposes at least a portion of the underlying CA contact 30. Somerecessing of the exposed portion of the CA contact 30 may occur duringthis etching process, but such recessing is not depicted in the attacheddrawings.

In the depicted example, the lateral width 105X of the opening 105A issuch that it overlaps the gate electrode 18 of one of the transistors.More specifically, the opening 105A exposes both the thinner (102A) andthicker (102B) portions of the non-uniform thickness layer of material102. Due to the presence of the thicker portions 102B of the non-uniformthickness layer of material 102 above the gate electrode, there is morematerial present to protect the gate electrode, e.g., the combinedthickness of the gate cap layer 20 plus the thicker portion 102B of thenon-uniform thickness layer of material 102. Additionally, the thickermaterial that is present above the gate electrode provides a greaterprocess window when performing the etching process as the etchingprocess does not have to be timed as accurately as when a uniformthickness layer of material (such as the layer 32 shown in FIG. 1D) wasformed above the gate cap layers 20. Moreover, due to the presence ofthe thicker portions 102B of the non-uniform thickness layer of material102, the lateral width 105X of the opening 105A, and the correspondingvia opening 102X, may be made larger, thereby resulting in a larger V0structure, which is desirable.

Next, as shown in FIG. 2F, after the patterned etch mask 105 wasremoved, known process operations were performed to form a conductive V0via 106 and a conductive metal line 108 in the M1 metallization layer.These conductive structures may be comprised of a variety of differentmaterials, e.g., copper, and may also include one or more barrier layers(not shown). In general, conductive materials may be formed in theopenings 102X and 104A, and one or more CMP processes may be performedto planarize the upper surface of the layer 104 and to remove excessconductive material positioned outside of the opening 104A. At the pointof fabrication depicted in FIG. 2F, additional metallization layers (notshown) may be formed above the M1 layer, e.g., M2/V1, M3/V2, etc.

FIGS. 3A-3J depict other illustrative methods disclosed herein forforming V0 structures for semiconductor devices and devices that includethe resulting V0 structural configurations. In this illustrative processflow, the CA contact 30 will be formed using a CA masking layer (notshown). FIGS. 3A-3J will depict the formation of a source/drain contactstructure above only the middle source/drain region 24 so as tofacilitate explanation of the present subject matter. Of course, thoseskilled in the art will appreciate that, in practice, a correspondingsource/drain contact structure will be formed for all of thesource/drain regions, i.e., on the source/drain region to the left ofthe gate structure 15A and on the source/drain region to the right ofthe gate structure 15B. FIG. 3A is a simplified view of an illustrativesemiconductor product 100 at an early stage of manufacturing after thesource/drain regions 24 and the gate structures were formed and after aplanarization process was performed on a layer of insulating material26, e.g., silicon dioxide. Thereafter, another layer of insulatingmaterial 27, e.g., silicon nitride or silicon dioxide, was formed abovethe gate cap layers 20 and the layer of insulating material 26. In thisexample, the gate structures may replacement gate structures wherein thecap layers 20 were formed after the materials for the replacement gatestructure were formed in the space (gate cavity) between the sidewallspacers 22 and recessed.

FIG. 3B depicts the product 100 after several process operations wereperformed to form a so-called self-aligned contact that is conductivelycoupled to the middle raised source/drain region 24. First, a patternedetch mask (a CA etch mask—not shown) was formed above the product 10 soas to expose the area between the gate structures 15A-15B. Thereafter,one or more etching processes were performed through the patterned CAetch mask to selectively remove portions of at least the layers ofinsulating material 26, 27 relative to the sidewall spacers 22 and thegate cap layer 20. This process operation exposes the raisedsource/drain region 24. Next, the patterned CA etch mask was removed andthe above-described trench silicide (TS) structure 28A was formed on theexposed source/drain region 24 by performing traditional silicideprocessing operations. Thereafter, a line-type CA contact structure 30comprised of, for example, tungsten, was formed so as to be conductivelycoupled to the trench silicide structure 28A. In one particular example,the line-type CA contact structure 30 may be formed by overfilling thearea above the trench silicide structure 28A with tungsten andthereafter performing a CMP process to planarize the upper surface ofthe layer 27 and thereby remove any excess conductive materials.

FIG. 3C depicts the product 100 after a recess etching process isperformed to remove at least some of the layer 27, and, in the depictedexample, substantially all of the layer 27 relative to the surroundingmaterials. This recess etching process exposes an upper portion of theCA contact structure 30.

Then, as shown in FIG. 3D, a layer of insulating material 120 was formedon the product 100 and a CMP process was performed. The layer ofinsulating material 120 may be comprised of a variety of differentmaterials, e.g., silicon nitride, etc., and it may be formed usingtraditional techniques, e.g., chemical vapor deposition (CVD), etc. Atthis point, the layer of insulating material 120 may have a thicknessthat falls within the range of about 15-30 nm. At the point depicted inFIG. 3D, the upper surface of the layer of insulating material 120 is ator near the same level as the upper surface of the CA contact structure30.

Next, as shown in FIG. 3E, a contact recess etching process is performedto reduce the height or thickness of the CA contact structure 30. Thisrecessing operation results in the formation of a CA contact etch cavity121 above the recessed CA contact structure 30. This recess etchingprocess also results in the formation of an opening 122 in the layer ofinsulating material 120. At this point in fabrication, the opening 122has a lateral width 122A.

FIG. 3F depicts the product after a timed isotropic etching process wasperformed on the layer of insulating material 120. This etching processhas the effect of increasing the lateral width of the opening 122 to alarger dimension 122B and also results in a thinning of the layer ofinsulating material 120, which has now been re-labeled with the number120A to reflect its reduced thickness. In one illustrative embodiment,the reduced thickness layer of material 120A may have a thickness ofabout 6-15 nm. This process operation also has the effect of increasingthe lateral width of the CA contact etch cavity 121, which has now beenre-labeled with the number 121A to reflect its increased lateral width.

FIG. 3G depicts the product 100 after several process operations wereperformed. First, a conformably deposited layer of insulating material124 is formed on the product 100. In one illustrative embodiment, thelayer of insulating material 124 may have a thickness of about 5-20 nm,and it may be formed by performing a conformal CVD process. The layer ofinsulating material 124 may only partially fill the CA contact etchcavity 121A. The layer of insulating material 124 may be comprised of avariety of different insulating materials, e.g., silicon nitride,N-Block, silicon oxynitride, silicon carbon boron nitride, etc. Next,the above-described layer of insulating material 104 was blanketdeposited above the product 100.

FIG. 3H depicts the product 100 after the layer of insulating material104 was patterned using a patterned etch mask (not shown) so as todefine the opening 104A in the layer of insulating material 104. Theopening 104A exposes a portion of the layer of insulating material 124for further processing.

FIG. 3I depicts the product 100 after several process operations wereperformed. First, a patterned etch mask 107 (such as a patterned layerof photoresist) having an opening 107A was formed above the product 100.The opening 107A corresponds to an opening for a V0 via that will beformed in the layer of insulating material 124 to establish electricalcontact to the underlying CA contact 30. So as to facilitateexplanation, only the formation of a V0 via for the middle CA contact 30will be depicted in the following drawings. Of course, as will beappreciated by those skilled in the art, a similar V0 via will be formedfor each of the CA contacts 30. Thereafter, an etching process wasperformed through the patterned etch mask 107 so as to define an opening124X in the layer of insulating material 124. The opening 124X exposesat least a portion of the underlying CA contact 30 (that was exposedprior to the formation of the layer of insulating material 124 (see FIG.3E)).

In the depicted example, the lateral width 107X of the opening 107A issuch that it overlaps the gate electrode 18 of one of the transistors onthe left. However, due to the presence of the reduced thickness layer ofmaterial 120A being positioned vertically above the gate electrode,there is more material present to protect the gate electrode, e.g., thecombined thickness of the gate cap layer 20 plus the thickness of thereduced thickness layer of material 120A. Additionally, by recessing theCA contact structure 30 (and thereby forming the CA contact etch cavity121 (or 121A) and the opening 122 in the layer of insulating material120/120A) prior to forming the layer of insulating material 124, thereis less protective material above the CA contact structure 30 than thereis above the gate electrode. This provides a greater process window whenperforming the etching process on the layer of insulating material 124as the etching process does not have to be timed as accurately as when auniform thickness layer of material (such as the layer 32 shown in FIG.1D) was formed above the gate cap layers 20 and the CA contact structure30. Moreover, due to the presence of the thicker portions of materialabove the gate electrodes, the lateral width 107X of the opening 107A,and the corresponding via opening 124X, may be made larger, therebyresulting in a larger V0 structure.

Next, as shown in FIG. 3J, after the patterned etch mask 107 wasremoved, known process operations were performed to form theabove-described conductive V0 via 106 and a conductive metal line 108 inthe M1 metallization layer. At the point of fabrication depicted in FIG.3J, additional metallization layers (not shown) may be formed above theM1 layer, e.g., M2/V1, M3/V2, etc.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

What is claimed:
 1. A method of forming a via on an integrated circuitproduct comprised of two spaced-apart transistor gate structures, eachof said gate structures having a gate cap layer with an upper surface,the method comprising: forming a source/drain contact structure betweensaid two spaced-apart transistor gate structures, wherein an uppersurface of said source/drain contact structure is positioned at a firstlevel that is above a level of said upper surfaces of said gate caplayers; recessing said source/drain contact structure to define arecessed source/drain contact having a recessed upper surface that ispositioned at a second level that is lower than said first level,wherein said recessing of said source/drain contact structure defines asource/drain contact etch cavity that is defined, at least in part, bysaid recessed upper surface of said recessed source/drain contact and afirst layer of insulating material; performing a conformal depositionprocess to deposit a conformal second layer of insulating material abovesaid first layer of insulating material, in said source/drain contactetch cavity and on said recessed upper surface of said recessedsource/drain contact; forming a third layer of insulating material abovesaid conformal second layer of insulating material; performing at leastone etching process to form an opening in said conformal second layer ofinsulating material so as to expose at least a portion of said recessedupper surface of said recessed source/drain contact; and forming saidvia such that it is conductively coupled to said exposed portion of saidrecessed source/drain contact structure, said via being at leastpartially positioned in said opening in said conformal second layer ofinsulating material.
 2. The method of claim 1, further comprising, afterforming said source/drain contact structure and prior to recessing saidsource/drain contact structure, removing insulating material positionedadjacent an upper portion of said source/drain contact structure andforming said first layer of insulating material adjacent said upperportion of said source/drain contact structure.
 3. The method of claim1, wherein said two gate structures are each a replacement gatestructure comprised of a gate insulation layer comprised of a high-kinsulating material and a gate electrode comprised of at least one layerof metal.
 4. The method of claim 1, wherein, after forming said thirdlayer of insulating material and prior to performing said at least oneetching process, the method further comprises forming an opening in saidthird layer of insulating material so as to expose a portion of saidconformal second layer of insulating material.
 5. The method of claim 1,wherein forming said via comprises forming said via such that a portionof said via is positioned vertically above said gate cap layer of atleast one of said two gate structures and above a portion of saidconformal second layer of insulating material having said opening formedtherein.
 6. The method of claim 1, wherein said first layer ofinsulating material is comprised of one of silicon dioxide or siliconnitride.
 7. The method of claim 1, wherein said conformal second layerof insulating material is comprised of one of silicon dioxide or siliconnitride.
 8. The method of claim 1, wherein said third layer ofinsulating material is comprised of a low-k insulating material.
 9. Themethod of claim 1, wherein, prior to performing said conformaldeposition process, the method comprises performing an isotropic etchingprocess to increase a lateral width of said source/drain contact etchcavity and reduce a thickness of said first layer of insulatingmaterial.
 10. A method of forming a via on an integrated circuit productcomprised of two spaced-apart transistor gate structures, each of saidgate structures having a gate cap layer with an upper surface, themethod comprising: forming a line-type trench silicide contact that isconductively coupled to a source/drain region positioned between saidtwo gate structures; forming a line-type source/drain contact structure(line-type CA contact structure) comprised of tungsten on said line-typetrench silicide contact, wherein an upper surface of said line-typesource/drain contact structure is positioned at a first level that isabove a level of said upper surfaces of said gate cap layers; recessingsaid line-type source/drain contact structure to define a recessedline-type source/drain contact structure having a recessed upper surfacethat is positioned at a second level that is lower than said firstlevel, wherein said recessing of said line-type source/drain contactstructure defines a source/drain contact etch cavity that is defined, atleast in part, by said recessed upper surface of said recessed line-typesource/drain contact structure and a first layer of insulating material;performing an isotropic etching process to increase a lateral width ofsaid source/drain contact etch cavity and reduce a thickness of saidfirst layer of insulating material; performing a conformal depositionprocess to deposit a conformal second layer of insulating material abovesaid first layer of insulating material, in said source/drain contactetch cavity with said increased lateral width and on said recessed uppersurface of said recessed line-type source/drain contact structure;forming a third layer of insulating material above said conformal secondlayer of insulating material; performing at least one etching process toform an opening in said conformal second layer of insulating material soas to expose at least a portion of said recessed upper surface of saidrecessed line-type source/drain contact structure; and forming said viasuch that it is conductively coupled to said exposed portion of saidrecessed line-type source/drain contact structure, said via being atleast partially positioned in said opening in said conformal secondlayer of insulating material.
 11. The method of claim 10, furthercomprising, after forming said line-type source/drain contact structureand prior to recessing said line-type source/drain contact structure,removing insulating material positioned adjacent an upper portion ofsaid line-type source/drain contact structure and forming said firstlayer of insulating material adjacent said upper portion of saidline-type source/drain contact structure.
 12. The method of claim 10,wherein, after forming said third layer of insulating material and priorto performing said at least one etching process, the method furthercomprises forming an opening in said third layer of insulating materialso as to expose a portion of said recessed upper surface of saidconformal second layer of insulating material.
 13. The method of claim10, wherein forming said via comprises forming said via such that aportion of said via is positioned vertically above said gate cap layerof at least one of said two gate structures and above a portion of saidconformal second layer of insulating material having said opening formedtherein.
 14. A method of forming a on an integrated circuit productcomprised of two spaced-apart transistor gate structures, each of saidgate structures having a gate cap layer with an upper surface, themethod comprising: forming a source/drain contact structure between saidtwo spaced-apart transistor gate structures, wherein an upper surface ofsaid source/drain contact structure is positioned at a first level thatis above a level of said upper surfaces of said gate cap layers, saidsource/drain contact structure being positioned at least partially in afirst layer of insulating material; removing at least a portion of saidfirst layer of insulating material; forming a second layer of insulatingmaterial comprised of silicon nitride to replace the removed portions ofsaid first layer of insulating material; recessing said source/draincontact structure relative to an upper surface of said second layer ofinsulating material so as to define a recessed source/drain contacthaving a recessed upper surface that is positioned at a second levelthat is lower than said first level, wherein said recessing of saidsource/drain contact structure defines a source/drain contact etchcavity that is defined, at least in part, by said recessed upper surfaceof said recessed source/drain contact and said second layer ofinsulating material; performing a conformal deposition process todeposit a conformal third layer of insulating material above said secondlayer of insulating material, in said source/drain contact etch cavityand on said recessed upper surface of said recessed source/draincontact; forming a fourth layer of insulating material above saidconformal third layer of insulating material; performing at least oneetching process to form an opening in said conformal third layer ofinsulating material so as to expose at least a portion of said recessedupper surface of said recessed source/drain contact; and forming saidvia such that it is conductively coupled to said exposed portion of saidrecessed source/drain contact structure, said via being at leastpartially positioned in said opening in said conformal third layer ofinsulating material.